A Study of the Effects of Oleuropein and Polydatin Association on Muscle and Bone Metabolism

Sarcopenia and osteoporosis are age-related musculoskeletal pathologies that often develop in parallel, and numerous studies support the concept of a bone–muscle unit, where deep interaction between the two tissues takes place. In Mediterranean areas, the lowest incidence of osteoporosis within Europe is observed, so the Mediterranean diet was suggested to play an important role. Consequently, in this study, oleuropein, a phenolic compound found in olive oil, and polydatin, another natural polyphenol found in the Mediterranean diet, were evaluated to determine their beneficial effects on bone and muscle metabolism. In human osteoblasts and skeletal muscle myoblasts, the effects were examined, and, after analyzing the cytotoxic effect to find non-toxic doses, the modulation of bone and muscle differentiation markers was evaluated at the gene and protein levels us- ing PCR, Western blot, and immunohistochemistry. Interestingly, the compounds increased markers involved in osteoblast differentiation, such as osteocalcin, type I collagen, and dentin-sialo-phosphoprotein, as well as markers involved in myoblast differentiation, such as myogenic regulatory factors and creatine kinase. These effects were most noticeable when the compounds were administered together. These results suggest a beneficial role for oleuropein–polydatin association on bone and muscle tissue pathologies simultaneously.